Heating system



Nov. 10, 1959 R. c. WINTZER 2,9

HEATING SYSTEM Filed April 15, 1955 INVENTOR RUDOLPH C. WINTZER W ATTORNEY United States Patent HEATING SYSTEM Rudolph C. Wintzer, Westfield, N.J., assignor to The Babcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Application April 15, 1955, Serial No. 501,687

4 Claims. (Cl. 237-58) This invention relates in general to an improved high temperature liquid heating system and, more specifically, the invention relates to a method and apparatus for heating hot water for such a system in a steam generating unit.

The pertinent hot water heating has such characteristics that it maintains the heating surfaces at a substantially uniform temperature, minimizes piping complicity by eliminating steam traps and reduces heating losses because there is no condensate or steam lost to the atmosphere. It, preferably, operates at pressures in the range of 60-240 p.s.i.g. and with water temperatures within the range of 300-400 F. Such temperatures make possible the use of the water as a source of heat for many applications besides space heating, such as providing heat for making low pressure steam in steam consuming processes, balking ovens and chemical processes where a uniform and high capacity supply of heat is required.

In the pasthot water systems, the cool liquid from the circulating system has been caused to pass through a combustion fired heat exchanger wherein the water rises in temperature and is delivered at some control-led temperature. Because, in such prior art systems, the temperature is well above the boiling point of water at atmospheric pressure, there is maintained a pressure on the system sufliciently high so as to preclude the water from boiling as it is being heated. Therefore, in such hot water systems, the Water temperature is always at a value below its boiling or saturated temperature, thus causing the water system to be designed for a pressure which is higher than the saturated boiling pressure of the water at the delivered temperature. A combustion fired hot water heater for such a system is exposed to a rather .large temperature gradient over the length of the hot water flow path in the heater. This creates a multi- ;plicity of temperature expansion problems in the tubes or pipes which must be accounted for by the design of the heater. This multiplicity of differential temperature \expansions requires that each section of the unit have :a different provision for a temperature expansion and :as such increases the complicity of the design, thus making the unit expensive.

Because there is no boiling taking place in the hot water heater, it is conventional to use a forced circulaftion type which requires that the safe operation of the Eheater be dependent upon the operation of a circulation pump. If for any reason the circulating pump fails, the high temperature products of combustion cause the stagnant water to boil and probably result in the rupture :of a tube or other damage to the heater.

The present invention is to a method of and apparatus :for high temperature liquid heating wherein a standard vapor generating unit supplies vapor to a direct heat transfer exchanger wherein the circulated low temperature liquid returning from the heating system passes in direct heat transfer with the generated vapor thereby condensing the vapor and heating the liquid. The return- -ing liquid from the hot liquid heating system is heated up to substantially saturated temperature, thus the design pressure of the heating system is at an absolute minimum for the hot liquid temperature utilized. Further, the vapor generator is a standard type of design into which is put the experience of years of building and operating such equipment and is the least expensive form of heat supply when compared to the special above mentioned combustion fired hot water heaters.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming apart of the specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawing and descr'ip tive matter in which there is illustrated and described a preferred embodiment of the invention.

In the drawing there is shown semi-schematically a hot Water system operating in accordance with the present invention. A steam generating unit 1, arranged for natural circulation having risers 2 through which the water is circulated and in which steam is generated, has.

the steam discharged into a steam water compartment, and then through a centrifugal or cyclone type steam water separator 4, preferably of the typeshown by the Fletcher and Rowand Patent 2,289,970 of July 14, 1942. The steam leaves the separatorv and passes over the baffle 5 into the vapor space 6 of the drum with the separated water being discharged through the bottom of the separator into the liquid space 7 of the drum 8. The steam generator is fired by the burners 9 and is controlled in a conventional manner, such as by controlling the firing rate from the pressure of the steam in the drum. A high temperature water heating system 10 is provided having a heat exchanger 11 giving up heat to any heat receiver which represents space and/or process heating. Theheat exchanger is fed circulated hot water from thedrum 8 by the pump 12 through the high temperature water lines 13' and the discharge or low temperature water line 14.- Thus, there is a complete circulation system whereby water is removed from the drum and after passing through the heating load is discharged backinto the drum. WA water level is maintained in the drum 8 by the controller 15 which operates the make-up feed valve 16 and blow down valve 17 so as to maintain the water level within reasonable limits within the drum.

Disposed Within the drum is a cold water or spray device 18 arranged so that the cold water returning from the heating system is sprayed into the vapor space 6 to effect condensation of the generated vapor with the resulant heating of the hot water system circulated water. The hot water system circulating pump 12 then draws the water from the water space 7 of the drum through the suction line 13. This spray device 18 constitutes then a direct heat transfer heat exchanger so that the steam which is provided by the conventional vapor generator is consumed in heating the hot water.

It is to be understod that the vapor generator shown is onlyrepresentative of the many types of vapor generators which can be used in the present invention. Any vapor generator in which there can be provided a containing vessel having a vapor space and a liquid space may be adapted to using the present invention.

This invention provides an improved hot water heating system in which the pressure parts are designed to carry only the minimum pressure for the design water temperature of the heating system and in so doing utilizes a conventional well known and inexpensive type of steam generator supplying saturated steam to heat the circulated hot water from the heating system indirect or contact heat transfer.

While the embodiment has been described with reference to water, any vaporizable liquid may be used to accomplish the same purpose.

While in accordance with the provisions of the statutes, there is illustrated and described herein a specific form of the invention. Those skilled in the art will understand that changes may be made in the embodiment of the invention disclosed, without departing from the invention as covered by the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

I claim:

1. A high temperature liquid heating system comprising, a vapor generating unit having a drum arranged with an upper vapor space and a lower liquid space, a bank of vapor generating tubes directly connected to said drum, liquid spray means disposed .to spray liquid into said vapor space of said drum, a heat exchanger directly connected to said and disposed at a position remote from said vapor generating .unit and arranged to transmit heat to a receiver, and means for continuously circulating saturated temperature liquid from the liquid space of said drum through said heat exchanger arranged to transmit heat to areceiver and thereafter returning at below saturated temperature to said drum through spray means, said spray means discharging said return liquid into said drum in direct heat transfer with the vapor whereby substantially all of vapor is condensed in heating said return liquid to saturated temperature and accumulates in said liquid space.

2. A high temperature water heating system comprising a unitary, compact steam generator including a series of steam generating tubes, a steam separating drum connected to said tubes, said drum having an upper steam space and a lower hot water space, a high temperature, closed circuit water heater remotely spaced from generator, said heater having a hot water inlet and relatively cold water outlet directly connected to the interior of said drum, said hot water inlet being in direct communication with said hot water space, means for .continuously circulating substantially saturated water from said water space of the drum through said remotely disposed hot water heater, said outlet including spray means for discharging the relatively cooled water of said heater into said steam space in direct heat transfer. relationship with the steam in said steam space so that substantially all of said steam generated by said steam generator is condensed within said drum and accumulated in said hot water space for recirculation through said heater.

3. A high temperature water heating apparatus comprising a steam generating unit having a drum arranged with an upper steam space and a lower saturated water space, a bank of steam generating tubes connected directly to said drum, said tubes discharging a steam and water mixture into said drum, a high temperature circulating water system including a heat exchanger connected directly to and remotely disposed from said drum in which saturated water is circulated from said drum through, said heat exchanger and thereafter returned'to said drum at below saturated temperature, said heat exchang r arranged for transmitting heat to a receiver.

4. A high temperature water heating apparatus comprising a steam generating unit having a drum arranged with an upper steam space and a lower saturated water space, a bank of steam generating tubes connected directly to said drum, said tubes discharging a steam and water mixture into said drum, a high temperature circulating Water system including a heat exchanger connected to and remotely disposed from said drum wherein saturated water is circulated from said drum through said heat exchanger and thereafter returned to said drum at below saturated temperature, said heat exchanger being arranged for transmitting heat to a receiver and means disposed within said drum for discharging said returned water at below saturated temperature into direct heat transfer with said generated steam wherein substantially all of said steam is condensed in heating said returned water to saturated temperature.

References Cited in the file of this patent UNITED STATES PATENTS 790,976 F'eck May 30, 1905 1,913,195 Donaldson et al. June 6, 1933 2,290,382 Keenan July 28, 1942 2,393,079 Wall Jan. 15 1946 2,669,976 Frisch Feb. 23, 1954 FOREIGN PATENTS 354,773 France Mar. 21, 1906 363,336 Great Britain 1932 475,767 Great Britain Nov. -25, 1937 

